// This example demonstrates verifying a secp256k1 signature against a public
// key that is first parsed from raw bytes.  The signature is also parsed from
// raw bytes.
func Example_verifySignature() {
	// Decode hex-encoded serialized public key.
	pubKeyBytes, err := hex.DecodeString("02a673638cb9587cb68ea08dbef685c" +
		"6f2d2a751a8b3c6f2a7e9a4999e6e4bfaf5")
	if err != nil {
		fmt.Println(err)
		return
	}
	pubKey, err := btcec.ParsePubKey(pubKeyBytes, btcec.S256())
	if err != nil {
		fmt.Println(err)
		return
	}

	// Decode hex-encoded serialized signature.
	sigBytes, err := hex.DecodeString("30450220090ebfb3690a0ff115bb1b38b" +
		"8b323a667b7653454f1bccb06d4bbdca42c2079022100ec95778b51e707" +
		"1cb1205f8bde9af6592fc978b0452dafe599481c46d6b2e479")

	if err != nil {
		fmt.Println(err)
		return
	}
	signature, err := btcec.ParseSignature(sigBytes, btcec.S256())
	if err != nil {
		fmt.Println(err)
		return
	}

	// Verify the signature for the message using the public key.
	message := "test message"
	messageHash := wire.DoubleSha256([]byte(message))
	verified := signature.Verify(messageHash, pubKey)
	fmt.Println("Signature Verified?", verified)

	// Output:
	// Signature Verified? true
}
func TestSignatures(t *testing.T) {
	for _, test := range signatureTests {
		var err error
		if test.der {
			_, err = btcec.ParseDERSignature(test.sig, btcec.S256())
		} else {
			_, err = btcec.ParseSignature(test.sig, btcec.S256())
		}
		if err != nil {
			if test.isValid {
				t.Errorf("%s signature failed when shouldn't %v",
					test.name, err)
			} /* else {
				t.Errorf("%s got error %v", test.name, err)
			} */
			continue
		}
		if !test.isValid {
			t.Errorf("%s counted as valid when it should fail",
				test.name)
		}
	}
}